Slap bass

I recently bought a bass book and ive got to the part where you learn how to slap. But the problem is i can't manage to pick the technique up, what it says is to hit the string at the end of the fretboard with your thumb(very very painful), is this right if not can any of you tell us how to.
And i am aware there is books and dvds about this but i have not got much mooney about at the moment.

I only have 20 frets, so I end up slapping between the pickup and the end of the fret board - I find it gives me more bounce off the string.

John-Paul - do you mean you can't get the sound, or it's just hurting? When I slap it doesn't hurt at all... I slap with the knuckle of my thumb - you need to slap the string and bounce it back off straight away - you get the *twang* sound then. You've gotta use your arm, wrist and thumb to get the right movement...

I slap like this:

* Rest my arm (just under my elbow) on the body of the bass, use that as a hinge
* Bring my arm out, turning my wrist to face the head / nut. Keep my fingers curled in (NOT a fist shape, just bend your fingers to the knuckle). This keeps them available for any pops you want in there.
* Bring my arm into the string I'm slapping, twisting my wrist / thumb back to be parallel with the string - I've heard of people that keep it parallel, but I keep my thumb pointing at a 45 degree angle downwards (My thumb is perfectly straight, there's no bend in it like most peoples!)
* Literally slap the string with the knuckle of your thumb - bring it down onto the string, hit it and rebound off. It's never hurt me - you must be doing something /really/ wrong for it to hurt?!
* After the rebound, you're ready for another attack. Be prepared for it to take ages to perfect... try slapping each string for 30 mins at a time - that's how I got semi-decent at it! Practice, practice, practice!

Obviously what I do won't be the same as everyone else, and it might not even be the most efficient way to do it! But I thought I'd give you the low-down

1. if it hurts, you're getting it right. no pain, no gain
2. if it hurts, you're doing it wrong. how can you play a gig like that?

my own technique has been shapeshifting over the last few years. I used to do a percussive slap between pickup and neck - NOT on the frets, but close. I'd head perpendicular, straight down, whack the string with the bit just above the actual knuckle, and quickly come back. I don't use the actual lumpy knuckle bit. it's bony there and it can hurt.

now, I go in at about a 45-degree angle with the same part of my thumb, which adds the option of hitting the string on the way back up (tricky, but can be a good technique). depending on what note is next, I can come off the string in a couple of different ways, but the 45-degree thing is working for me. Then again, I've evolved towards it instead of picking it up right away

I'll say this though - I've rarely felt pain just slapping. Learning the up-pluck/pop thing, yes. I blistered. down/up/pluck? yes, I bled. down/up/pluck/pluck? haven't got it yet, but I keep catching the knuckle of my little finger on the pickguard screws. more blood.

Keep at it though - slap is the best fun. and don't worry too much about doing it by the book - develop a style you like the sound and feel of.